Blind stitch sewing machines

ABSTRACT

An improvement in blind stitch sewing machines having a needle carrier supporting a curved blind stitch needle oscillatable through an arc to penetrate the work, which arc is closely adjacent other parts of the machine so that replacing or threading of the needle is difficult because of the limited space available. Means are therefore provided whereby the needle carrier is manually releasably carried on its shaft so that when it is necessary to replace or thread the needle it may be manually rotated on its shaft up out of the way of other parts of the machine where such work is easily accomplished.

United Statess-Patent 1 Krasnitz et, al.

[ 1 May 22,1973

1541 BLIND STITCH SEWING MACHINES [76] Inventors: Jacob Krasnitz, 1739 W. Addison, Chicago, 111. 60613; Martin Krasnitz, 8024 Lyons, Chicago, 111. 60648; Ronald M. Spatzek, 1355 N. Sondbury Terrace, Chicago, HI. 60610; Ronald H. Krasnitz, 7759 S. Shore Drive, Niles, HI. 60649 [22] Filed: Aug. 27, 1971 [21] Appl. N0.: 175,618

[52] US. Cl ..1l2/176, 112/221 [51] Int. Cl. ..D05b 1/24 [58] Field ofSearcli ..1l2/176, 177,221;

[56] References Cited UNITED STATES PATENTS 3,606,849 9/1971 Forte et al. ..1 12/176 Primary Examiner-H. Hampton Hunter Attorney-Sabin C. Bronson [57] ABSTRACT An improvement in blind stitch sewing machines having a needle carrier supporting a curved blind stitch needle oscillatable through an arc to penetrate the work, which are is closely adjacent other parts of the machine so that replacing or threading of the needle is difficult because of the limited space available. Means are therefore provided whereby the needle carrier is manually releasably carried on its shaft so that when it is necessary to replace or thread the needle it may be manually rotated on its shaft up out of the way of other parts of the machine where such work is easily accomplished.

4 Claims, 19 Drawing Figures BLIND STITCH SEWING MACHINES BACKGROUND SUMMARY DRAWINGS The present invention relates to blind stitch sewing machines and more particularly to a new and improved needle shaft arrangement for facilitating the threading of the needle.

Blind stitch sewing machines of the general type to which the present invention relates are illustrated and described in U. S. Pat. Nos. 1,926,644 and 1, 926,761 both dated Sept. 12, 1953, US. Pat. No. 2,514,837 dated July 1 1, 1950. These machines are characterized by a curved needle which is mounted on an end of a needle shaft. The shaft is horizontally supported and oscillated through a predetermined angle so that the needle is penetratable through a bight in layers of cloth that is brought into the arc of movement of the needle by a rib. The rib is movable up and down so that the needle penetrates through the layers in a preselected location to form blind stitches and the like in the well known manner.

The needle mounting arrangement and the angle of oscillation of the shaft in these prior machines is such that it is awkward to replace and adjust the needle mounted on the shaft. This difficulty is caused primarily by the fact that even at the limit of the shaft oscillation the body and point of the needle are located in close proximity to the work holder.

By the present invention it is proposed to provide an arrangement for permitting free rotation of the clamped needle relative to the longitudinal axis of the needle shaft so that the needle may be displaced beyond the normal angle of oscillation of the shaft and spaced sufficiently above the work table so that the needle may be removed and replaced without interference.

In one form of the invention the blind stitch sewing machine comprises a needle shaft oscillatable about the longitudinal axis thereof. A needle carrier is mounted on the end of the shaft and holds the needle clamped. The needle carrier is turnable on the needle shaft. Detent means mounted in a fixed angular position on the shaft and is seatable in an opening in the needle carrier to hold the latter fixed against rotation and thereby position the needle for stitching. The detent is released from the opening to permit the carrier to be freely rotatable about the shaft so that the needle may be removed or be replaced in location free of interference from the work table.

In another embodiment of the invention the blind stitch needle shaft is made in sections of which one section is connected to the actuating means for oscillating the shaft. The needle carrier and needle are fixed to the other of the sections. Keying means are provided to rigidly connect the sections for concurrent oscillation so that the needle on the other of the shafts swings through the limited angle of oscillation in the usual manner. The keying means is arranged so that the needle carrying section may be released from driving or oscillating engagement with the other section so that it may be freely rotated. The needle carrying section may be rotated sufficiently to permit the needle to be displaced clear of the work table.

Further features of the invention will appear hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary end of a blind stitch sewing machine embodying the needle shaft arrangement of the present invention;

FIG. 2 is a fragmentary top plan view of the head of the blind stitch sewing machine;

FIG. 3 is a fragmentary front elevational view of the head taken generally along the lines 3-3 of FIG. 1;

FIG. 4 is a fragmentary rear elevational view of the head taken generally along the lines 4-4 of FIG. 1:

FIG. 5 is a cross-sectional view taken generally along the lines 5-5 of FIG. 2 and showing the needle carrier clamped in a fixed angular position on the needle shaft;

FIG. 6 is a cross-sectional view similar to FIG. 5 but showing the needle carrier freely rotatable about the needle shaft to a position in which the needle may be threaded;

FIG. 7 is a view similar to FIG. 6 but showing a modified detent arrangement for releasably positioning the needle carrier;

FIG. 8 is a fragmentary front elevational view of a blind stitch sewing machine having a second embodiment of needle shaft arrangement for facilitating the threading of the needle;

FIG. 9 is a cross sectional-view of the needle shaft arrangement taken generally along the lines 9-9 of FIG.

FIG. 10 is similar to FIG. 9 but showing the needle shaft arrangement in a needle release position so that the needle'carrying section is freely rotatable about the longitudinal axis thereof;

FIG. 11 is a cross sectional-view taken generally along the lines of 11-11 of FIG. 9;

FIG. 12 is a cross-sectional view taken generally along the lines 12-12 of FIG. 9;

FIG. 13 is a cross-sectional view taken generally along the lines 13-13 of FIG. 9;

FIG. 14 is a fragmentary front elevational view of a blind stitch machine having a further embodiment of a needle shaft arrangement;

FIG. 15 is a fragmentary cross-sectional view of the needle shaft arrangement taken generally along the lines 15-15 of FIG. 14;

FIG. 16 is a fragmentary cross-sectional view similar to FIG. 15 but showing a modification of the detent means that may be used to maintain the shaft sections fixed against rotation relative to each other;

FIG. 17 is a fragmentary cross-sectional view of a needle shaft showing another modification for coupling the shaft section;

FIG. 18 is a cross-sectional view taken generally along the lines 18-18 of FIG. 17;

FIG. 19 is a cross-sectional view taken generally along the lines 19-19 of FIG. 18.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1-6 of the drawings there is shown a blind stitch sewing machine 10 comprising one embodiment of a needle shaft arrangement 11 particularly adapted for use on existing blind stitch sewing machines. The sewing machine 10 comprises generally a frame 12 including a head 13 and a bed 14. An oscillatable ridge member 16 is mounted on the bed 14 and serves to bring plys or layers of material into the path of movement of a needle 17 in the well known manner.

The needle 17 is of the curved type and is clamped at one end at the terminal end of an arm 18 of a needle carrier 19. The needle carrier 19 is formed with a boss 20 having an opening 21 which turnably accommodates a needle shaft 22 which is horizontally mounted in the head 13. The needle shaft 22 is oscillated about its longitudinal axis in the well known manner by means not shown.

The blind stitch sewing machine described above is of more or less standard construction and reference is made to the aforementioned patents for a more detailed description of the structure and the operation.

As shown particularly in FIG. 1 the needle 17 is in close proximity to the bed 14 even in the outer limits of oscillation thereof. This condition makes it difficult to thread the needle 17 because of the limited space in which the fingers may be inserted. In accordance with the embodiment of the invention shown in FIGS. 1-6 the needle shaft 22 includes a substantially U-shaped member 23 having a bight 24 and a pair of legs 26 and 27. The leg 26 is formed with an opening 28 through which the needle shaft 22 extends. A slot 29 extends from the opening 28 to the outer edge so that upon the tightening of a screw 31 the leg 26 is securely clamped to the needle shaft 22. The other leg 27 terminates in a somewhat arcuate edge 32 which lies in close proximity to the needle shaft 22.

A detent screw 33 is threaded through the bight portion of the U-shaped member 23. The detent screw 33 terminates in a detent head 34 which is seatable in a radial opening 36 provided in the needle carrier boss 20. When thus seated in the radial opening 36 the detent screw 33 is effective to maintain the needle carrier 17 clamped to the needle shaft 22. In this manner the needle 17 is fixed for oscillation with the needle shaft 20. It is to be noted that the counterclockwise movement, as viewed in FIG. 5, of the needle carrier 19 relative to the U-shaped member 23 is limited by stop or locating stud 37 projecting from the leg 26.

To release the needle 17 from oscillation with the needle shaft 22 the detent screw 33 is threaded outwardly so that the detent head 34 is unseated from the radial opening 26. This permits the needle carrier 19 to be freely rotated about the needle shaft 22 so as to be rotatable beyond the normal limits of oscillation of the shaft 22 to the position shown in FIG. 6. In this position the needle 17 is spaced above the sewing machine bed 14 a distance adequate to facilitate the threading thereof.

A spring detent means 38, as shown in FIG. 7, may be substituted for the detent screw 33. The spring detent means 38 includes a detent pin 39 disposed in a chamber 41 formed on the inside surface of the bight 24 and projecting outwardly through an opening 40. The detent pin 39 includes a shoulder 42 against which one end of a biasing spring 43 bears to urge the detent pin 39 outwardly against the boss. The detent pin 39 includes a detent head 44 which is seatable within the radial opening 36 under the force exerted by the biasing spring 43 when the opening 36 and pin 39 are aligned. The needle 17 is thus fixed for oscillation with the shaft 22. Release of the needle carrier 19 from oscillation with the needle shaft 22 is accomplished by grasping the projecting end of the detent pin 39 until the detent head 43 is unseated. The carrier arm is then free to be rotated about the longitudinal axis of the needle shaft 22 to the needle threading position shown in FIG. 7.

Referring now to FIGS. 8-13 there is shown another embodiment of the invention in which the means for facilitating the threading of the needle is incorporated into a new design of blind stitch sewing machine. To this end a novel needle shaft is provided into a blind stitch sewing machine 101 which is similar to the sewing machine 10 described in connection with the embodiments of FIGS. 1-7.

The novel needle shaft 100 comprises a pair of sections 101 and 102 which are releasably coupled together by a coupling arrangement 103. The shaft section 101 is connected at one end to the shaft oscillating mechanism, and the shaft section 102 has a needle carrier 19a fixedly clamped thereon for turning movement therewith. The needle carrier 19a has a curved needle 17a clamped thereon. A collar 104 also clamped to the needle shaft 100 prevents inward longitudinal movement of the carrier arm 19a.

The shaft section 101 at the inner end thereof has a longitudinally extending radial slot 105 in which a key 106 is slidably disposed. The key 106 includes an inclined surface 107 at the leading end thereof and a ledge 108 at the trailing edge as shown in particular in FIG. 13. The key 106 is normally biased outwardly by a biasing spring 109 into a quadrant like slot 111 provided in the inner end of the short section 102. The quadrant like slot 111 has a wall 112 against which one of the sides 113 of the key 106 is adapted to bear. The bearing relationship of the wall 112 and the side 113 prevents relative counterclockwise rotation, of the shaft sections 101 and 102.

For preventing clockwise rotation, a sleeve 114 is fixedly secured to the inner end of the shaft section 101 by means of set screws 116. The sleeve 114 receives the inner end of the other shaft section 102 and is provided with a semi-circular slot 117. A radially projecting stop screw 118 is threaded into the shaft section 102 and is accommodated within the semi-circular slot 117. The stop screw 118 is located so as to engage the end 119 of the slot so as to prevent counter-clockwise rotation of the shaft section 102 relative to the shaft section when the key 106 is in abutting relation with the quadrant wall 112. In this manner the location of the stop screw 118 in engagement with the wall 119 prevents counter-clockwise turning and the key 106 in engagement with the slot wall 112 prevents clockwise movement so as to prevent back lash between the sections 101 and 102 during oscillation.

To release the shaft section 102 from the section 101 so that the needle carrier 19a and thereby the needle 17a clamped thereon may be turned to a position similar to that shown in FIG. 7, there is provided a release rod 121. The release rod 121 is slidably disposed in an axially extending bore 122 and projects outwardly at the needle carrying end of the shaft section 102 and into a bore 124 formed at the inner end of the shaft section 101. The bore 124 communicates with the radial slot 104 so that the inner end of the release rod 121 is engageable with the ledge 108. Thus, to release the key 106 from engagement with the quadrant like slot wall 112, the release rod 121 is pushed inwardly so that the inner end in engagement with the ledge 108 forces the key 106 out of the slot 111 against the force of the biasing spring 109. This permits the shaft section 102 to be rotated relative to the section 101 to a position in which the needle 17a is easily threaded.

Turning now to FIGS. 14 and 15 there is shown another modification of a blind stitch machine 210 similar to that shown in the embodiment of FIGS. 7-13 and having a different type of coupling arrangement for coupling shaft sections of a blind stitch needle shaft 200. The blind stitch needle shaft 200 includes a shaft section 201 connected to the needle shaft oscillating mechanism in the usual manner and a shaft section 202 on which the needle carrier 19a is clamped.

Fixed to the inner end of the needle shaft 201 as by means of welding is a sleeve 203. The sleeve 203 turnably receives the adjacent end of the shaft section 202 which is held against axial movement relative to the shaft section 201 by a ring key 204. Disposed in an axial bore 205 extending through the shaft section is a release rod 206. The release rod 206 includes a head 207 which is disposed in an enlarged counterbore passage 208 formed coaxial with the bore 205. A biasing or compression spring 209 is disposed in an enlarged passage and serves to normally bias the rod to the right with the head 207 in engagement with an annular shoulder 211 as shown in FIG. 15.

A passage 213 radially extends through the sleeve 203 and is axially aligned with a radial passage 212 communicating with the bore 205. Disposed in the radial passage 212 and extending into the passage 213 is a detent in the form of a ball 214. In the position shown in FIG. 15 the diameter of the ball detent 214 is located approximately at the outer diameter of the shaft section 202 and the inner diameter of the sleeve 203. In this manner the ball detent 214 prevents relative rotation between the sleeve 203 and shaft section 202 so that the latter is concurrently oscillated with the shaft section thereby to oscillate the needle carrier 19a.

The shaft section 202 is released from oscillation with the shaft section 201 by depressing the release rod inwardly to compress the spring 209 until a reduced neck portion 216 is aligned with the passage 212. When the passage 212 and the reduced neck portion 216 are aligned, the ball detent 214 drops downwardly clear of slot 213 in the sleeve 203. The shaft section is then free to be rotated relative to the sleeve 203 and the shaft section 201 so as to be freely rotatable for selectively positioning the needle carrier 19a to thread the needle.

The shaft sections 201 and 202 are locked or coupled for concurrent oscillation when the pushing force on the rod 206 is released and the biasing spring 209 bearing against the rod 206 returns the ball detent 214 and the reduced neck sections to the position shown in FIG. 15.

An alternative form of detent arrangement as shown in FIG. 16 may be used in the embodiment of FIGS. 14 and 15. The detent arrangement comprises a pin 221 slidably disposed in the passages 212 and 213 and in the locked position as shown and being biased radially inward by a spring 224 located in the passage 213. The spring 224 is retained in the passage by a band 223. The spring biased detent 221 is operative to couple and 'release the shaft sections 201 and in the same manner as described in connection with FIGS. 14 and 15.

Turning now to FIG. 17-19 inclusive there is shown another form of needle shaft and coupling arrangement for permitting free rotation of one shaft section to the other. As shown the needle shaft 300 comprises a shaft section 301 adapted to be connected to the needle shaft oscillating means and a shaft section 302 to which the needle is fixed. A sleeve 303 is fixed at one end to the inner end of the shaft section 301 and receives the shaft section 302 in the other end. The shaft section 302 is held against axial displacement in the sleeve 303 by means of a ring washer 304. The ring washer 304 permits the shaft section 302 to rotate in the sleeve 303. The inner end of the shaft section 301 is formed with a diametrically extending slot 306 and an axial bore 307 in which a compression spring 308 is located. The spring 308 nonnally urges a rectangular key 309 disposed in the slot 306 into a diametrically extending slot 311 formed on the inner end of the shaft section 302. The shaft 301 and 302 are thus coupled for concurrent oscillation.

A release rod 313 located in an axial bore 314 and having a head 316 disposed in an enlarged countersink bore 317 serves to release the shaft sections for independent turning movement. Upon depression of the release rod 313 in the direction of the arrow shown in FIG. 18, the key 309 is moved to the left against the spring 308 until the key is disposed completely out of the slot 311. This permits the shaft section 302 to be turned relative to the shaft section 301 and facilitates the threading of the needle carried thereon.

To reconnect the shaft section 302 for oscillation with the shaft section 301 the shaft section 302 is rotated until the slot 31 1 is in alignment with the key 309. The biasing spring 308 is then free to seat the key 309 into the 311. Thus the key 307 is seated in both of the slots 306 and 311 formed in the shaft sections 301 and 302, respectively, so that the latter are keyed for concurrent oscillation.

We claim:

1. A blind stitch sewing machine comprising an oscillatable needle shaft, a needle carrier mounted on said shaft, said needle carrier having a boss including a bore receiving said shaft for turnably mounting said carrier on said shaft, a radial opening in said boss and communicating with said bore, a detent mounting means separate from said needle carrier secured to said oscillatable needle shaft and mounting said detent against separate turning movement about said needle shaft, said detent being mounted on said mounting means for radial movement for engagement only within said radial opening in said boss whereby said needle carrier is fixed for oscillation with said oscillatable shaft, and for movement out of engagement with said radial opening whereby said needle carrier is free to turn about said shaft. 7

2. The blind stitch machine as defined in claim 1 wherein said mounting means comprises a U-shaped member having a bight and a pair of legs, and means clamping at least one of said legs of said member on said shaft, and wherein said detent means is mounted on said bight.

3. The blind stitch machine as defined in claim 2 wherein said detent is threaded in said bight for movement axially of said detent into and out of engagement with said radial opening.

4. The blind stitch machine as defined in claim 2 wherein spring means is mounted on said bight for coacting with said detent so that said detent is normally biased into engagement with said radial opening and is manually retractable out of engagement with said opening.

t t l i 

1. A blind stitch sewing machine comprising an oscillatable needle shaft, a needle carrier mounted on said shaft, said needle carrier having a boss including a bore receiving said shaft for turnably mounting said carrier on said shaft, a radial opening in said boss and communicating with said bore, a deteNt mounting means separate from said needle carrier secured to said oscillatable needle shaft and mounting said detent against separate turning movement about said needle shaft, said detent being mounted on said mounting means for radial movement for engagement only within said radial opening in said boss whereby said needle carrier is fixed for oscillation with said oscillatable shaft, and for movement out of engagement with said radial opening whereby said needle carrier is free to turn about said shaft.
 2. The blind stitch machine as defined in claim 1 wherein said mounting means comprises a U-shaped member having a bight and a pair of legs, and means clamping at least one of said legs of said member on said shaft, and wherein said detent means is mounted on said bight.
 3. The blind stitch machine as defined in claim 2 wherein said detent is threaded in said bight for movement axially of said detent into and out of engagement with said radial opening.
 4. The blind stitch machine as defined in claim 2 wherein spring means is mounted on said bight for coacting with said detent so that said detent is normally biased into engagement with said radial opening and is manually retractable out of engagement with said opening. 